3D-display systems have existed in a variety of forms for many years. Generally, these systems convey a sense of depth by presenting slightly different views of a similar image to each of a viewer's eyes. Conventional systems have employed color filters (such as the red/cyan glasses), type of light-polarization, or polarization angles, and require filters placed near the eyes. More recently, displays have been developed that can present 3D images without requiring the use of such filters. These displays, for example, often employ lenticular lenses or parallax barriers, etc. Such display systems are known as autostereoscopic displays.